1 institute of particle science and engineering, leeds 2 school of earth and environment, leeds

DIAMOND Decommissioning, Immobilisation and Management of Nuclear Wastes for Disposal

Physical Modelling of Impinging Jets to aid Nuclear Sludge bed resuspension

1Institute of Particle Science and Engineering, Leeds2School of Earth and Environment, Leeds

Chetan Lakhanpal1

Project Supervisors:Prof. Simon Biggs1, Prof. Mike Fairweather1, Dr Jeff Peakall2


Physical Modelling of an Impinging Jet on a Settled Bed

Contents

Ұ Problem Description

Ұ Project Objectives

Ұ Experimental facilities & Measurement techniques

Ұ Preliminary Work

Ұ Plans for future

Ұ Questions



Problem Description

Legacy nuclear waste exist around various sites through out the world

Settling out of solid particles hinders attempts to process waste, activity may generate thermal hot spots leading to corrosion and equipment damage

Jet impingement used to re-suspend particles that form solid beds in storage ponds, tanks and silos

Re-suspension characteristics of particles never studied using appropriate simulants

Project will use experimental and numerical modelling to improve understanding and provide predictive capability for use in design, and optimisation of storage and processing arrangements

Timely given development of experimental rigs at NNL to study impinging flows of relevance to particle re-suspension in high level waste plants, and industry interest in the development of Sludge Packaging Plant No. 1, both of which use impinging jets, in the form of pulse jet mixers, for sludge mobilization



Problem Description

Figure showing finned metallic container to store waste from Magnox programme



Problem Description

Figure showing Magnesium Hydroxide sludge sample



Problem Description

Figure showing a typical HAS tank



Experimental Work

Stage 1a: Orthogonal single phase jet impingement on flat plate

Stage 1b: Comparison of results with those of other researchers

Stage 2: Dilute multi phase jet impingement on flat plate

Stage 3: Multi phase jet impingement on flat plate

Stage 4: Multi phase jet impingement on settled beds



Experimental Rig



Experimental Rig

Feed / over -flow tanks



Measurement Techniques

Particle Image Velocimetry (PIV) Ultra Doppler Velocity Profiling (UDVP)



Preliminary Work Single phase jet impingement studies

The Impingement of a jet on a flat surface



Preliminary Work Single phase jet impingement studies

The Wall Jet

Poreh et al. (1961)



Dye Experimentation

• To track fluid flow

• Parameters:

• Single phase, water in water

• Jet-to-plate separation = 2d

• Re = 20k



Dye Experimentation



Dye Experimentation VFA

a

b d

c



Ultrasonic Doppler Velocity Profiling

y: vertical dist. from base; d: diameter of jet; U: velocity at a radial location; Vb: bulk velocity



Comments

• Two layer shear flow phenomena noticed on jet impingement

• Qualitative understanding gained using Dye work and UDVP

• Jet Impingement is a complex 3d flow, parameters need to be optimized for different configurations.

Reynolds number, tracer particle concentration, UVP parameters

• Good quantitative data can be obtained in far field regions using UVP

• PIV to be used for near field mapping



Plans for Future

• Mean velocity and turbulence characteristics at 5d and 10d separations

• Particle Characterization Studies

• Move to multiphase jet impingement on settled beds

• Particle Size, Density, Solids Concentration, Fluid Viscosity,

Particle size distribution, Particle shape, Zeta Potential, pH,

Settling behaviour, Solids packing fraction, Yield stress



Thank you for your attention.

Any questions.

1 institute of particle science and engineering, leeds 2 school of earth and environment, leeds

Documents